Rotating machinery, transformers and other systems frequently produce undesirable vibration and resulting noise. Several efforts have been made at minimizing vibration of some of these systems. One method is to apply a compensating force to the system at a sufficient magnitude and phase to minimize the vibration. In order to determine the compensating force to be applied it is necessary to provide means such as transducers for measuring the vibration and also means for applying a compensating force of known value to the system. Typically, velocity transducers or accelerometers are used to measure the vibration and actuators may be used to apply a compensating force. An initial compensating force of zero is applied to the system and the vibration of the system is measured One then computes a change to make in the compensating force, subtracts the change from the initial compensating force and applies a new force to the system. If the process is repeated over and over again, the vibration output will eventually reach a minimum value. The difficulty with previous systems is that in some situations an unreasonable number of iterations is required before a minimum value is reached. Very often the minimum value cannot be reached because an unacceptable number of iterations is required. Consequently, there is a need for a method of quickly adjusting a compensating force to minimize vibrations.
Typically the prior art has used a single sensor to monitor vibration and a single actuator to apply the compensating force. This arrangement has not been useful for large transformers and other equipment which have several vibrating surfaces. For large complex systems it is desirable to measure the vibration at many locations and to apply compensating forces at several locations. However, prior art systems were not capable of handling multiple outputs and multiple inputs. Until the present invention, the art has been unable to repeatedly process multiple sensor outputs to generate multiple actuator inputs within reasonable amount of time. Consequently, there is a need for a system which can detect vibration from multiple points and which can apply compensating forces at multiple points different from the locations of the force sources.